Rapid local address assignment for wireless communication networks

ABSTRACT

A wireless client device includes a receiver and a connection module. The receiver is configured to receive, on a wireless medium of a wireless network, a management frame that is periodically transmitted on the wireless medium. The management frame includes an address assignment indication that indicates which address assignment types are employed by the wireless network. The connection module is configured to, in response to the address assignment indication indicating that a dynamic address assignment type is employed by the wireless network, configure a network-layer address for the wireless client device according to a dynamic address assignment protocol. The connection module is configured to, in response to the address assignment indication indicating that the dynamic address assignment type is not employed by the wireless network, configure the network-layer address for the wireless client device according to a link-local address assignment protocol.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 13/568,641(now U.S. Pat. No. 8,446,843), filed on Aug. 7, 2012, which is acontinuation of U.S. patent application Ser. No. 12/549,464 (now U.S.Pat. No. 8,238,315), filed on Aug. 28, 2009, which claims the benefit ofU.S. Provisional Application No. 61/097,380, filed on Sep. 16, 2008, andU.S. Provisional Application No. 61/099,739, filed on Sep. 24, 2008. Theentire disclosures of the above applications are incorporated byreference herein.

BACKGROUND

The present disclosure relates generally to the assignment of InternetProtocol (IP) addresses in wireless networks. More particularly, thepresent disclosure relates to increasing the speed of the assignment ofIP addresses in wireless networks such as wireless local-area networks(WLANs).

Networking technologies such as WLAN require that a unique networkaddress be assigned to each communicating device. IPv4 and IPv6 are thestandard protocols used for these network communications, and haveseveral ways in which the unique IPv4 or IPv6 device addresses can beassigned. The types of address assignment include static addressing,where the addresses are manually assigned by an administrator; dynamicaddressing, where addresses are automatically assigned by a server, forexample according to Dynamic Host Configuration Protocol (DHCP); andlink-local addressing, where addresses are automatically assignedwithout a server.

Link-local addressing is useful in networks that are formed in an ad-hocmanner. These networks can include Wi-Fi Infrastructure, Wi-Fi IBSS, orWi-Fi peer-to-peer networks. Such networks do not havecentrally-coordinated address assignment or DHCP servers. According toapplicable standards, a device having a link-local addressing mechanismfirst checks whether a DHCP server is available by sending DHCPrequests. The device must retransmit the DHCP request multiple timesbefore determining, after a significant delay, that no DHCP server isavailable. Only then does the device use link-local addressing to obtaina local address.

This delay presents a significant usability problem. Establishing anetwork connection between two devices can take 30 to 60 seconds just todetermine whether DHCP is available. These long delays severely impactthe user experience of mobile device connectivity.

SUMMARY

In general, in one aspect, an embodiment features an apparatuscomprising: a receiver to receive a first wireless signal from awireless network; an address module to determine a type of InternetProtocol address assignment employed by the wireless network based onthe first wireless signal; and a connection module to establish anetwork-layer connection to the wireless network based on the type ofInternet Protocol address assignment determined by the address module.

In general, in one aspect, an embodiment features a computer programcomprising: instructions for determining a type of Internet Protocoladdress assignment employed by a wireless network based on a firstwireless signal received from the wireless network; and instructions forestablishing a network-layer connection to the wireless network based onthe type of Internet Protocol address assignment determined by theaddress module.

In general, in one aspect, an embodiment features an apparatuscomprising: a transmitter to transmit a first wireless signal, whereinthe first wireless signal represents an indication of a type of InternetProtocol address assignment employed by a wireless network connected tothe apparatus.

In general, in one aspect, an embodiment features a computer programcomprising: instructions for causing transmission of a first wirelesssignal from a device, wherein the first wireless signal represents anindication of a type of Internet Protocol address assignment employed bya wireless network connected to the device.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features will beapparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows elements of a communication system comprising a wirelessnetwork, a connected wireless communication device, and a connectingwireless communication device according to one embodiment.

FIG. 2 shows a process for the communication system of FIG. 1 accordingto one embodiment where the connecting wireless communication deviceprompts the connected wireless communication device to transmit awireless signal that indicates the type of IP address assignmentemployed by the wireless network.

FIG. 3 shows a process for the communication system of FIG. 1 accordingto one embodiment where the connected wireless communication devicetransmits a signal that indicates the type of IP address assignmentemployed by the wireless network without prompting from the connectingwireless communication device.

FIG. 4 shows a process for the communication system of FIG. 1 accordingto one embodiment where the connecting wireless communication devicedetermines the type of IP address assignment employed by the wirelessnetwork based on wireless signals received from the connected wirelesscommunication device that do not include an indication of the type of IPaddress assignment employed by the wireless network.

The leading digit(s) of each reference numeral used in thisspecification indicates the number of the drawing in which the referencenumeral first appears.

DESCRIPTION

Embodiments of the present disclosure provide elements of acommunication system for rapid local address assignment. FIG. 1 showselements of a communication system 100 comprising a wireless network 102according to one embodiment. In some embodiments, wireless network 102is implemented as a wireless local-area network (WLAN). In someembodiments, wireless network 102 is implemented in other ways. Althoughin the described embodiments, the elements of communication system 100are presented in one arrangement, other embodiments may feature otherarrangements. For example, elements of communication system 100 can beimplemented in hardware, software, or combinations thereof.

Referring to FIG. 1, communication system 100 also includes a wirelesscommunication device 104 connected to wireless network 102 and awireless communication device 106 connecting to wireless network 102.For clarity, wireless communication device 104 is referred to herein as“connected” wireless communication device 104, while wirelesscommunication device 106 is referred to herein as “connecting” wirelesscommunication device 106.

Connected wireless communication device 104 includes a transmitter 108,a receiver 110, and a controller 112. Connecting wireless communicationdevice 106 includes a transmitter 114, a receiver 116, an address module118, and a connection module 120. Each of wireless communication devices104 and 106 can be implemented as a switch, router, network interfacecontroller (NIC), and the like. In some embodiments, connected wirelesscommunication device 104 can be implemented as an access point or thelike.

According to various embodiments, connecting wireless communicationdevice 106 determines the type of IP address assignment employed bywireless network 102 based on signals received by connecting wirelesscommunication device 106 from wireless network 102, for exampleincluding signals transmitted by connected communication wireless device104. Connecting wireless communication device 106 then connects towireless network 102 using the determined type of IP address assignment.This technique can greatly increase the speed of local addressassignment, and therefore can greatly reduce the time required toconnect to the network. For example, if connecting wirelesscommunication device 106 determines that dynamic addressing is not used,connecting wireless communication device 106 can avoid checking whethera DHCP server is available by sending DHCP requests, thereby reducingnetwork connection time by 30 to 60 seconds. Three embodiments aredescribed below in detail. Other embodiments will be apparent afterreading this disclosure.

In some embodiments, connecting wireless communication device 106prompts connected wireless communication device 104 to transmit awireless signal that indicates the type of IP address assignmentemployed by wireless network 102 FIG. 2 shows a process 200 forcommunication system 100 of FIG. 1 according to one such embodiment.Although in the described embodiments, the elements of the processesdisclosed herein are presented in one arrangement, other embodiments mayfeature other arrangements, as will be apparent based on the disclosureand teachings provided herein. For example, in various embodiments, someor all of the steps of the disclosed processes can be executed in adifferent order, concurrently, and the like.

Referring to FIG. 2, transmitter 114 of connecting wirelesscommunication device 106 transmits a wireless signal representing arequest for an indication of the type of IP address assignment employedby wireless network 102 (step 202). Receiver 110 of connected wirelesscommunication device 104 receives the wireless signal (step 204). Inresponse, controller 112 of connected wireless communication device 104generates an indication of the type of IP address assignment employed bywireless network 102 (step 206).

Transmitter 108 of connected wireless communication device 104 transmitsa wireless signal that represents the indication of the type of IPaddress assignment employed by wireless network 102 (step 208). In someembodiments, the wireless signal transmitted by connecting wirelesscommunication device 106 represents an IEEE 802.11 Probe Request Frame,and the wireless signal transmitted by connected wireless communicationdevice 104 represents an IEEE 802.11 Probe Response Frame. In otherembodiments, both wireless signals represent IEEE 802.11 Action Frames.In these IEEE 802.11 embodiments, the indication can be provided as anInformation Element. In some embodiments, Wi-Fi Protected Setup (WPS)protocols defined by the Wi-Fi Alliance are used to carry thisinformation in a secure manner, either alone or to securely augment theinformation carried by beacons and probes. Of course, other messages canbe used, for example including link-level messages such as ExtensibleAuthentication Protocol (EAP) messages, Logical Link Control (LLC)messages, unassociated multicast messages, and the like.

The indication of the type of IP address assignment employed by wirelessnetwork 102 can indicate a link-local address assignment type, a dynamicaddress assignment type, a static address assignment type, and the like.Alternatively, the indication can indicate the type(s) of IP addressassignment that are not available. For example, the indication couldindicate that dynamic addressing is not available.

Receiver 116 of connecting wireless communication device 106 receivesthe wireless signal (step 210). Based on the indication in the wirelesssignal received from connected wireless communication device 104,address module 118 of connecting wireless communication device 106determines the type of IP address assignment employed by wirelessnetwork 102 (step 212). Connection module 120 of connecting wirelesscommunication device 106 then establishes a network-layer connection towireless network 102 based on the type of IP address assignmentdetermined by address module 118 (step 214). Thereafter, connectedwireless communication device 104 communicates with wireless network 102using that connection (step 216).

In some embodiments, connected wireless communication device 104transmits a signal that indicates the type of IP address assignmentemployed by wireless network 102 without prompting from connectingwireless communication device 106. FIG. 3 shows a process 300 forcommunication system 100 of FIG. 1 according to one such embodiment.

Referring to FIG. 3, controller 112 of connected wireless communicationdevice 104 generates an indication of the type of IP address assignmentemployed by wireless network 102 (step 302). Transmitter 108 ofconnected wireless communication device 104 transmits a wireless signalthat represents the indication of the type of IP address assignmentemployed by wireless network 102 (step 304). In some embodiments, thewireless signal transmitted by connected wireless communication device104 represents an IEEE 802.11 Beacon Frame. The indication of the typeof IP address assignment employed by wireless network 102 can indicate alink-local address assignment type, a dynamic address assignment type, astatic address assignment type, and the like. Alternatively, theindication can indicate the type(s) of IP address assignment that arenot available. For example, the indication could indicate that dynamicaddressing is not available.

Receiver 116 of connecting wireless communication device 106 receivesthe wireless signal (step 306). Based on the indication in the signalreceived from connected wireless communication device 104, addressmodule 118 of connecting wireless communication device 106 determinesthe type of IP address assignment employed by wireless network 102 (step308). Connection module 120 of connecting wireless communication device106 then establishes a network-layer connection to wireless network 102based on the type of IP address assignment determined by address module118 (step 310). Thereafter, connected wireless communication device 104communicates with wireless network 102 using that connection (step 312).

In some embodiments, connecting wireless communication device 106determines the type of IP address assignment employed by wirelessnetwork 102 based on wireless signals received from connected wirelesscommunication device 104 that do not include an indication of the typeof IP address assignment employed by wireless network 102. FIG. 4 showsa process 400 for communication system 100 of FIG. 1 according to onesuch embodiment.

Referring to FIG. 4, receiver 116 of connecting wireless communicationdevice 106 receives a wireless signal transmitted by transmitter 108 ofconnected wireless communication device 104 (step 402). The receptiontechniques employed can include packet sniffing, snooping, directreception, and the like.

Based on the wireless signal, address module 118 of connecting wirelesscommunication device 106 determines the type of IP address assignmentemployed by wireless network 102 (step 404). For example, address module118 can determine the type of IP address assignment based on the type ofaddresses observed in packets represented by the wireless signal. Forexample, address module 118 could observe the IP address of connectedwireless communication device 104 in the wireless signal. Address module118 can tell if wireless network 102 employs link-local addressing byobserving that the IP address is a link-local address. As anotherexample, address module 118 can determine the type of IP addressassignment based on the observation of a Time-To-Live (TTL) parameterrepresented by the wireless signal. Of course, other characteristics ofthe packets represented by the wireless signal can be used.

Connection module 120 of connecting wireless communication device 106then establishes a network-layer connection to wireless network 102based on the type of IP address assignment determined by address module118 (step 406). Thereafter, connected wireless communication device 104communicates with wireless network 102 using that connection (step 408).

Various embodiments can be implemented in digital electronic circuitry,or in computer hardware, firmware, software, or in combinations of them.Embodiments can be implemented in a computer program product tangiblyembodied in a machine-readable storage device for execution by aprogrammable processor; and method steps can be performed by aprogrammable processor executing a program of instructions to performfunctions by operating on input data and generating output. Embodimentscan be implemented in one or more computer programs that are executableon a programmable system including at least one programmable processorcoupled to receive data and instructions from, and to transmit data andinstructions to, a data storage system, at least one input device, andat least one output device. Each computer program can be implemented ina high-level procedural or object-oriented programming language, or inassembly or machine language if desired; and in any case, the languagecan be a compiled or interpreted language. Suitable processors include,by way of example, both general and special purpose microprocessors.Generally, a processor will receive instructions and data from aread-only memory and/or a random access memory. Generally, a computerwill include one or more mass storage devices for storing data files;such devices include magnetic disks, such as internal hard disks andremovable disks; magneto-optical disks; and optical disks. Storagedevices suitable for tangibly embodying computer program instructionsand data include all forms of non-volatile memory, including by way ofexample semiconductor memory devices, such as EPROM, EEPROM, and flashmemory devices; magnetic disks such as internal hard disks and removabledisks; magneto-optical disks; and CD-ROM disks. Any of the foregoing canbe supplemented by, or incorporated in, ASICs (application-specificintegrated circuits).

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made without departingfrom the scope of the disclosure. Accordingly, other implementations arewithin the scope of the following claims.

What is claimed is:
 1. A wireless client device, comprising: a receiverconfigured to receive, on a wireless medium of a wireless network, amanagement frame that is periodically transmitted on the wirelessmedium, wherein the management frame includes an address assignmentindication that indicates which address assignment types are employed bythe wireless network; and a connection module configured to (i) inresponse to the address assignment indication indicating that a dynamicaddress assignment type is employed by the wireless network, configure anetwork-layer address for the wireless client device according to adynamic address assignment protocol, and (ii) in response to the addressassignment indication indicating that the dynamic address assignmenttype is not employed by the wireless network, configure thenetwork-layer address for the wireless client device according to alink-local address assignment protocol.
 2. The wireless client device ofclaim 1, wherein the management frame is periodically transmitted by awireless access point of the wireless network.
 3. The wireless clientdevice of claim 1, wherein the management frame comprises a beacon framethat is compatible with IEEE 802.11.
 4. The wireless client device ofclaim 1, wherein the dynamic address assignment protocol comprisesdynamic host configuration protocol (DHCP).
 5. The wireless clientdevice of claim 1, wherein the network-layer address is an InternetProtocol (IP) address.
 6. The wireless client device of claim 1, furthercomprising a transmitter configured to transmit on the wireless mediumusing the network-layer address.
 7. The wireless client device of claim6, wherein the transmitter is configured to transmit packets from thewireless client device, wherein a source address of each of the packetsis set to the network-layer address.
 8. The wireless client device ofclaim 1, wherein the connection module is configured to, in response tothe address assignment indication indicating that the dynamic addressassignment type is not employed by the wireless network, avoidconfiguring the network-layer address for the wireless client deviceaccording to the dynamic address assignment protocol.
 9. The wirelessclient device of claim 1, further comprising a transmitter configured totransmit an address request in order to configure the network-layeraddress for the wireless client device according to the dynamic addressassignment protocol.
 10. The wireless client device of claim 9, whereinthe address request comprises a dynamic host configuration protocol(DHCP) request.
 11. A method of operating a wireless client device, themethod comprising: receiving, on a wireless medium of a wirelessnetwork, a management frame that is periodically transmitted on thewireless medium, wherein the management frame includes an addressassignment indication that indicates which address assignment types areemployed by the wireless network; in response to the address assignmentindication indicating that a dynamic address assignment type is employedby the wireless network, configuring a network-layer address for thewireless client device according to a dynamic address assignmentprotocol; and in response to the address assignment indicationindicating that the dynamic address assignment type is not employed bythe wireless network, configuring the network-layer address for thewireless client device according to a link-local address assignmentprotocol.
 12. The method of claim 11, wherein the management frame isperiodically transmitted by a wireless access point of the wirelessnetwork.
 13. The method of claim 11, wherein the management framecomprises a beacon frame compatible with IEEE 802.11.
 14. The method ofclaim 11, wherein the dynamic address assignment protocol comprisesdynamic host configuration protocol (DHCP).
 15. The method of claim 11,wherein the network-layer address is an Internet Protocol (IP) address.16. The method of claim 11, further comprising communicating on thewireless network using the network-layer address.
 17. The method ofclaim 16, wherein the communicating on the wireless network comprisestransmitting packets from the wireless client device, wherein a sourceaddress of each of the packets is set to the network-layer address. 18.The method of claim 11, further comprising, in response to the addressassignment indication indicating that the dynamic address assignmenttype is not employed by the wireless network, avoiding configuring thenetwork-layer address for the wireless client device according to thedynamic address assignment protocol.
 19. The method of claim 11, whereinthe configuring the network-layer address for the wireless client deviceaccording to the dynamic address assignment protocol comprisestransmitting an address request message.
 20. The method of claim 19,wherein the address request message comprises a dynamic hostconfiguration protocol (DHCP) request.